1. Field of Invention
This invention relates to a music information highway in which a plurality of subscribers are linked by a network to a central computer station in whose memory is stored a library of music scores, each defined by the nominal notation of a particular composition.
2. Status of Prior Art
My prior U.S. Pat. Nos. 4,763,257 and 4,707,682 disclose a computerized system into which is fed the nominal values of a musical score, the system acting to process these values with respect to the relative loudness of different tones in a succession thereof, changes in the duration of the tones and other deviations from the nominal values which together constitute the microstructure or microscore of the music notated by the score. The system yields the specified tones of the score as modified by the microscore, thereby imparting expressivity to the music that is lacking in the absence of the microscore.
Music has been defined as the art of incorporating intelligible combinations of tones into a composition having structure and continuity. A melody is constituted by a rhythmic succession of single tones organized as an aesthetic whole. The standard system of notation employs characters to indicate tone. The duration of a tone (whole, half, quarter, etc.) is represented by the shape of the character, and the pitch of each tone by the position of the character on a staff.
While the notation of a musical score gives the nominal values of the tones, in order for a performer to breathe expressive life into the composition, he must read into the score many nuances that are altogether lacking in standard notation. Some expressive subtleties are introduced qualitatively as a matter of accepted convention, but virtually all departures from the nominal values appearing in the score depend on the interpretive power of the performer.
Thus, a musical score, may indicate whether a section of the score is to be played loudly (forte) or softly (piano) without however indicating a quantitative relation between forte and piano. And the score does not generally specify the relative loudness of component tones either of a melody or of a chord with anything approaching the degree of discrimination required by the performer. The performer therefore must decide for himself how loudly specific notes are to be played to render the music expressive.
Equally important to an effective performance of most music is the amplitude contour of each tone in the succession thereof. To satisfy musical requirements, the amplitude envelopes of the tones must be individually shaped. Though, in general, amplitude contours are completely unspecified in standard notation, each performer, such as a singer or violinist who has the freedom to shape tones, does so in actual performance to impart expressivity thereto. Indeed, with those instruments that lend themselves to tone shaping, variations in the amplitude shapes of the tones constitute a principal means of expression in the hands of an expert performer.
Another factor which comes into play in the microstructure of music are subtle deviations from the temporal values prescribed in the score. Thus, in actual performance, to avoid temporal rigidity which dehumanizes music, and to impart meaningful expression thereto, the performer will in actual practice amend the nominal duration values indicated by standard notation. They should not be amended in a random way as is often the case in synthetic music, but in a manner imparting meaning and feeling to the music.
Yet another expressive component of music which is unspecified in the score is the timbre to be imparted to each tone; that is, the harmonic content thereof. A performer of a string instrument, by varying the pressure and velocity of the bow on the string, can give rise, not only to variations in the loudness of the tone, but also variations in its tonal timbre both from one note to another and within each tone, independently of loudness. Still another expressive component is the vibrato imparted to each tone which also varies in nature from tone to tone.
In short, the "macrostructure" of a musical composition is defined in the score by standard notation. If, therefore, one executes this score by being assiduously faithful only to the notes as given in the score, the resultant performance, however expertly executed, will be bereft of vitality and expression. The term "microscore" as used herein encompasses all subtle deviations from the nominal values of the score in terms of amplitude size and shaping, timing, timbre, vibrato and all other factors which endow music with feeling and expressiveness.
Essential to an understanding of a microscore in the context of a system in accordance with the invention are A. the inner pulse of composers and B. predictive amplitude shaping. These will now be separately considered.
In the computerized system disclosed in my prior patents, fed therein are the nominal values of a musical score, the system acting to process these values with respect to the amplitude contour of individual tones, the relative loudness of different tones in a succession thereof, changes in the duration of the tones, vibrato, timbre and other deviations from the nominal values which together constitute the microscore of the music notated by the music score. The system produces the specified tones in the score as shaped and modified by the microscore, thereby imparting expressivity to the music that is lacking in the absence of the microscore. The microscore may also include changes in pitch.
In order to produce convenient shapes for creating amplitude envelopes of individual tones, we have used a mathematical means, briefly called the Beta Function. This term derives from a similarly-named function in mathematical statistics. The Beta Function permits us to create a wide variety of shapes with the aid of only two parameters (P.sub.1 and P.sub.2).
In electronic generation of musical sounds, it has heretofore been conventional to specify tones using parameters of rise time, decay time, sustain time, release time and final decay, or some subset or multiple set of these. These parameters, familiar to the electronic engineer, modeled on a piano key action, do not really have an appropriate musical function in representative musical thought. Amplitude shapes of musical tones often need to be convex rather than concave (or vice versa) in particular portions of their course (e.g., convex in their termination), and hardly ever have sustained plateaux. Moreover, separation of the termination of a tone into a decay and a release is generally the result of the mechanical properties of keyboard instruments and not a musical requirement.
We have found that the varied rounded forms available through the Beta Function allow a more faithful, simple and time-economical realization of the multitude of nuances of musical tone amplitude forms.
A computerized system as disclosed in my prior patents acts to impart an emotionally-expressive microstructure or microscore to the respective notes in the score of a musical composition constituted by a succession of notes whose notation provides the nominal value for each note in regard to its pitch and duration. The system comprises a digital calculator and means to enter therein nominal data representing the nominal pitch and duration of each of the successive notes in the musical score to be processed. Also included is a matrix having stored therein microscore data relating to the relative loudness and duration values of a series of notes forming a group (say 4 sixteenth notes) representing the inner pulse of a given musical composer, aspects of the ethnic character of the music, or merely aspects of that piece of music, that is a specific combined time and amplitude warp; and means to enter into the calculator this microscore data.
The matrix can operate simultaneously on several levels of the structure, forming an array of elements each of which has a different loudness and amplitude. A 4.times.4.times.4 array for example has 64 such elements. Attenuation factors are provided to regulate the degree to which the amplitude and time warps are effective on each hierarchic level.
The calculator acts to process the nominal data entered therein with reference to the microscore data also entered therein to yield in its output with respect to each note in the succession thereof a series of digital values representing loudness and duration changes in accordance with their interrelationship to the inner pulse of the composer, and also to contour the amplitude of each note in accordance with its relationship to the succeeding note, called predictive amplitude shaping. Also included are means responsive to this output to generate and audibly reproduce tones representing the notes of the musical score as modulated by the microscore data to render the reproduced music derived from the score expressive.
The system disclosed in my prior patents includes a keyboard or other means making it possible for the user to enter the successive tones of a given musical score in terms of their nominal pitch and duration expressed in alpha-numeric terms.
The present invention takes into account that there is a vast literature of musical compositions whose printed scores are available. Even in the classical field, this literature encompasses many thousands of scores. While one could provide a computer system of the type disclosed in my prior patents with a CD ROM or other forms of memory in which hundreds of scores are stored, operating in conjunction with means to feed into the system any one of the selected scores so that it can be expressively reproduced, this arrangement may involves capital expenses of a relatively expensive system of this type, as well as reduced convenience.